Telephone-receiver.



H. R. STUART & E. 0. KIZER.

TELEPHONE RECEIVER.

APPLICATION FILED APR. 19, 1909.

Patented Apr. 26, 1910.

UNITED STATES PATENT OFFICE.

HARVE R. STUART AND EDWIIl' O. KIZER, OF WHEELING, WEST VIRGINIA.

TELEPHONE-RECEIVER.

To all whom it may concern:

Be it known that we, HARVE R. STUART and EDWIN O. Krznn, citizens of the United States, residing at \Vheeling, in the county of Ohio and State of \Vest Virginia, have invented certain new and useful Improvements in Telephone-Receivers, of which the following is a specification.

Our invention relates to telephones, and particularly to the receivers thereof.

The object of the invention is to provide a telephone receiver that shall comprise a small number of parts so constructed and arran ed as to permit of ready and accurate assem ling and adjustment thereof and in such a manner as to produce an instrument of extreme sensitiveness.

The invention is illustrated in the accompanying drawing Figure. 1 of which is a ront view of the receiver, the upper half of the casing and the diaphragm of which are removed. Fig. 2 is a sectional view of the receiver with certain of the parts somewhat separated for the sake of more clearly bringing out their construction. Fig. 3 is a face view of the magnet of the receiver.

The receiver of Figs. 1 and 2 comprises an annular shaped magnet 1 havingan inwardly extending polar projection '2 that is provided with an aperture disposed approximatelyconcentrically with the annular portion, the magnet being so magnetized that the projection 2 constitutes one pole thereof and the diametrically opposite portion of the annulus constitutes the other pole.

\ .The magnet 1 is mounted in the back member 3 of the receiver casing, and is secured in position by means of screws 4 that roject through the casing and are threaded at their inner ends into nuts 5 and 6, the latter of which is longer than the former and serves as one of the pole pieces of the magnet, and is accordingly mounted upon the annular portion thereof diametrically opposite the polar projection 2. Suitably secured, as by sweating or soldering, to the back of the casing member 3 is an internally- 1 threaded magnetlzable member or nut 7, into which is screwed one end of a pole piece 8 that is threaded from end to end, and is provided in its outer end face with a slot 9 that permits of the use of a screw-driver for adjusting its position, and thereby also the distance between its end face and the diaphra m 10. Threaded upon the pole piece 9 an supporting a coil 11, is a bobbin 12,

Specification of Letters Patent.

Patented Apr. 26, 1910.

Application filed April 19, 1909. Serial No. 490,761.

cemented or otherwise secured to one end face of which is a washer 13' that is electrically connected to one terminal of the coil 12. The washer 13 engages the polar projection 2 of the magnet 1, and thus connects one terminal of the coil 12 to one terminal of the transmission line, thereby eliminating the necessity of making one connection to the coil during assembling of the device and providing a more substantial connection.

The polar projection 2 of the magnet l is clamped between the washer 13 and the nut 7, a magnetic path of low reluctance be ing thus established between the polar projection 2 and the pole piece 8 through the nut 7. The magnet 1 may accordingly be made from a punching, and it is unnecessary to machine or otherwise finish it either before or after tempering. The distance between th'e end of the ole piece 8 and the diaphragm 10 maybe readily and conveniently adjusted when asscmblin gor at any other time, so as to secure tie most sensitive conditions of operation, and the bobbin 12 and the washer 13 will serve as a lock nut to maintain the pole piece in any position to which it may be ad usted. lt will be ob served that the advantageous features just described are secured with but a very small number of parts.

We claim as our invention:

- 1. A telephone receiver comprising a magnet, a pole piece therefor, a supporting mema coil surrounding the pole piece, a bobbin therefor threaded upon the pole piece, and

a conducting plate upon an outer end of the bobbin that is connected to the coil, the magnet being clamped between the conducting plate and the said member.

2. A telephone receiver comprising a magnet having an apertured pole, a pole piece of smaller diameter than the aperture in the magnet and that projects therethrough, a member into which one end of the pole piece is threaded, a bobbin threaded upon the other end of the pole piece and between which and the said member the apertured pole of the magnet is clamped.

3. A telephone receiver comprislng a casing, a magnet within the same, a pole piece for the magnet, a member secured to the easing into which the pole piece is threaded, and a bobbin'threaded upon the pole piece and adapted to clamp the magnet between substantially the same and thelsaid memberand to lock the pole piece in position.

4.- A magnet conslsting of acomplete' a11- nulus and an inwardly extending projection therefrom, the poles being located, re-

' 6. A telephone receiver comprising an annular magnet provided with an inwardly extending polar projection, a pole piece, a member into which the pole piece is threaded, a bobbin threaded upon the pole piece between which and the said member the polar projection of the magnet is clamped.

In testimony whereof we .afiixour signav tures in pres'ence of two witnesses.

HARVE R. STUART. EDWIN O. KIZER.

Witnesses:

U. S. SANDS, H. E. HOHMANNJ. 

